Systems and methods for wafer pod alignment

ABSTRACT

In an embodiment, a wafer pod includes: a cavity configured to receive and store a wafer; an alignment fiducial within the cavity, wherein: the alignment fiducial comprises two lines orthogonal to each other, and the alignment fiducial is configured to be detected by a robotic arm alignment sensor disposed on a robotic arm, wherein the alignment fiducial defines an alignment orientation for a robotic arm gripper hand to enter into the cavity.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 15/883,509 filed Jan. 30, 2018, now U.S. Pat. No. 10,741,433,which claims priority to U.S. Provisional Patent Application No.62/592,068, filed on Nov. 29, 2017, each of which are incorporated byreference herein in their entireties.

BACKGROUND

Modern assembly line manufacturing processes are typically highlyautomated to manipulate materials and devices and create a finishedproduct. Quality control and maintenance processes often rely on humanskill, knowledge and expertise for inspection of the manufacturedproduct and manufacturing process.

Typical assembly line processes for processing wafers (e.g.,semiconductor devices or materials) employ no specific inspectiontechniques at a robotic arm for alignment with a wafer carrying pod,also termed as a wafer pod, aside from manual inspections. Examples ofwafer pods include standard mechanical interface (SMIF) pods which mayhold a plurality of wafers, or front opening unified pods (FOUPs) whichmay hold larger wafers.

Alignment is important as a robotic arm that is not aligned with a waferpod may place or retrieve wafers from the wafer pod in a manner thatdamages the wafer. For example, a non-aligned robotic arm may damage awafer by impacting the wafer carried by the non-aligned robotic armagainst a side, front, or rear wall of the wafer pod. However,conventional manual inspection and alignment techniques require largeamounts of overhead and expensive hardware, but still fail to producesatisfactory results. Therefore, conventional inspection techniques arenot entirely satisfactory.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that various features are not necessarily drawn to scale. In fact,the dimensions and geometries of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1A is a top cross sectional view of a robotic arm disposed relativeto a wafer pod, in accordance with some embodiments.

FIG. 1B is a top cross sectional view of a dummy wafer deployed within awafer pod, in accordance with some embodiments.

FIG. 2A is a partial transparency diagram of a wafer pod with analignment fiducial, in accordance with some embodiments.

FIG. 2B is a side cross sectional view of a wafer pod with an alignmentfiducial, in accordance with some embodiments.

FIG. 3 is a partial transparency diagram of a wafer pod with a centerpoint sensor, in accordance with some embodiments.

FIG. 4 is a block diagram of various functional modules of a wafer podalignment functional module, in accordance with some embodiment.

FIG. 5 is a flow chart of a wafer pod alignment placement process, inaccordance with some embodiments.

FIG. 6 is a flow chart of a wafer pod alignment retrieval process, inaccordance with some embodiments.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following disclosure describes various exemplary embodiments forimplementing different features of the subject matter. Specific examplesof components and arrangements are described below to simplify thepresent disclosure. These are, of course, merely examples and are notintended to be limiting. For example, it will be understood that when anelement is referred to as being “connected to” or “coupled to” anotherelement, it may be directly connected to or coupled to the otherelement, or one or more intervening elements may be present.

In addition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

The present disclosure provides various embodiments of automated waferpod alignment with a robotic arm gripper hand. A robotic arm gripperhand may be automatically aligned for entry within a cavity of a waferpod. The cavity may be any opening within a wafer pod configured toreceive and hold a wafer. This automatic alignment may utilize sensorson both or either the robotic arm (that includes the robotic arm gripperhand) and the wafer pod. For example, the robotic arm may include analignment sensor to determine an alignment orientation of the roboticarm gripper hand to a fiducial within the cavity of the wafer pod.Positioning the gripper hand in the alignment orientation may ensurethat the robotic arm may enter into the cavity of the wafer pod with awafer that is clear of any side walls of the wafer pod (e.g., that therobotic arm entry is centered). Also, the robotic arm gripper hand mayutilize a center point sensor within the wafer pod to determine how farextended the robotic arm gripper hand should extend into the cavity ofthe wafer pod without causing a wafer to impact a rear or front walls(e.g., a door) of the wafer pod. In contrast, conventional alignment forrobotic arm gripper hand entry into a wafer pod is performed manuallyand not in an automated manner.

FIG. 1A is a top cross sectional view 100 of a robotic arm 102 disposedrelative to a wafer pod 104, in accordance with some embodiments. Therobotic arm 102 may include a gripper hand 106 configured to grip andmanipulate a wafer 105. The wafer 105 is illustrated in phantom with adotted line outline. The gripper hand 106 may include a number offingers 108 which are configured to extend under and support a wafer ontop of the fingers 108. The fingers may include a gripper surface thatmakes physical contact with a wafer in order to secure, manipulate, andmove the wafer. The top cross sectional view 100 may include a top crosssectional view of the wafer pod 104 and a top view of the robotic arm102.

The robotic arm 102 may include an alignment sensor 110. The alignmentsensor 110 may be configured to sense alignment with a fiducial 111located along a surface of the cavity of the wafer pod 104. Thealignment may be along an axis of entry 112 which defines a straightpath into the wafer pod 104 in a manner that allows the wafer 105 to notimpact a sidewall 114 during entry into the cavity. As will be discussedin greater detail below, the alignment fiducial 111 may be a line alongthe axis of entry 112 and along a floor 116 within a cavity of the waferpod 104. Although the alignment fiducial may be discussed as along afloor 116, in other embodiments the alignment fiducial 111 may be alonga ceiling instead of a floor or, in yet other embodiments, along both aceiling and a floor of the cavity of the wafer pod 104.

The alignment fiducial 111 may be a straight line fiducial to along theaxis of entry 112. As will be discussed further below and although notillustrated in FIG. 1A, the alignment fiducial 111 may also be along therear wall 118 of the cavity of the wafer pod 104. Stated another way,the alignment fiducial 111 may be a vertical straight line fiducialalong a rear wall 118 of the cavity and also longitudinal line along thefloor 116 of the cavity. Accordingly, when aligned with the alignmentfiducial 111, the gripper hand 106 may be controlled to move in a mannerrestrained along two degrees of freedom.

In particular embodiments, the alignment sensor 110 may include a laseremitter that emits a laser which is sensed in reflection by a lasersensor collocated with the laser emitter. In other embodiments, thelaser emitted by the laser emitter may be sensed directly by analignment fiducial sensor along the alignment fiducial 111. In suchembodiments, the alignment sensor on the robotic arm may communicatewith the alignment fiducial sensor and only include a laser emitterwithout a laser sensor, or may include both a laser emitter and a lasersensor. The laser emitter may include a photoelectric emitter that emitscollimated radiation (e.g., light) as a line or beam that terminates ina point. The laser sensor maybe configured to sense collimatedradiation. For example, the laser sensor may be an image sensorconfigured to determine when the collimated radiation of the laseremitter aligns with the alignment fiducial along both the floor 116 andthe back wall 118. When the laser emitter emits radiation as a point(e.g., along a beam terminating in a point), the laser emitter may bemounted on a sensor platform and moved in a controlled manner along asingle degree of freedom so as to have a terminus of the collimatedradiation traverse the length of the alignment fiducial 111. In such anembodiment, the robotic arm 102 may move (e.g., rotate) the platformalong a degree of freedom so that the point radiation of the laseremitter may traverse (e.g., confirm alignment) with the alignmentfiducial 111 along both the floor 116 and the back wall 118. When thelaser emitter emits radiation as a line, the laser sensor may confirmthat the emitted line is aligned with the alignment fiducial 111 alongboth the floor 116 and the back wall 118. The alignment fiducial 111will be discussed further below at least in connection with FIG. 2A.

In various embodiments, the wafer 105 may be a dummy wafer 105A. Thedummy wafer 105A may be used for initial alignment and subsequentlyreplaced with non-dummy wafers to be transported in the wafer pod 104.The dummy wafer 105A may include a center point fiducial 120. Also, thewafer pod 104 may include a center point sensor 122. The center pointsensor 122 may be configured to detect when the center point fiducial120 is at a center point of the wafer pod 104. Stated another way, thecenter point sensor 122 may be configured to sense when the center pointfiducial 120 of a dummy wafer 105A is at a central vertical axis of thecavity of the wafer pod. The central vertical axis may be at a pointalong both the axis of entry 112 and a side axis 124 but orthogonal toboth the axis of entry 112 and the side axis 124. An amount of entryinto the wafer pod 104 before the center point sensor 122 detects thecenter point fiducial 120 may be recorded as a displacement depth. Thisdisplacement depth may be stored (e.g., recorded in a data store forfuture retrieval) so that the amount of entry may be repeated forsubsequent entry of the robotic arm gripper hand into the cavity of thewafer pod 104.

FIG. 1B is a top cross sectional view 125 of the dummy wafer 105Adeployed within the wafer pod 104, in accordance with some embodiments.When deployed, the dummy wafer 105A may be transported by the gripperhand 106 into the wafer pod 104 so that the center point fiducial 120 ofthe dummy wafer 105A may be detected by the center point sensor 122. Thecenter point sensor 122 may be configured to sense along the centralvertical axis (e.g., above or below the center point sensor 122) at acenter point of the wafer pod 104 where a wafer is to be centered at.Accordingly, the gripper hand 106 transport the dummy wafer 105A intothe wafer pod 104 along the axis of entry 112 by using the alignmentsensor 110 to ensure alignment with a fiducial along the axis of entry112. Also, the gripper hand may stop entry of the dummy wafer 105A intothe cavity of the wafer pod 104 when the center point sensor 122 detectsthe center point fiducial 120 of the dummy wafer 105A. The amount ofdisplacement (e.g., displacement depth value) of the gripper hand 106into the cavity of the wafer pod 104 at the point of detection of thecenter point fiducial 120 by the center point sensor 122 may be termedas a displacement depth. The displacement depth may be recorded andutilized to determine an amount of displacement utilized in subsequenthandling of wafers so that the gripper hand 106 does not extend tooclose or too far into the cavity of the wafer pod 104 to cause thewafer, held by the gripper hand 106, to impact the rear wall 118 of thewafer pod 104 and/or a door 126 or front wall of the wafer pod 104.

FIG. 2A is a partial transparency diagram of a wafer pod 202 with analignment fiducial 204, in accordance with some embodiments. The waferpod 202 may be hollow, with a cavity 206 and a door 208, drawn inphantom with dotted lines, to allow for ingress and egress from thecavity 206 of the wafer pod 202. The sides of the wafer pod 202 mayinclude exterior grips 210 or handles to facilitate movement of thewafer pod 202. The wafer pod 202 is illustrated as a partialtransparency diagram 200 in which features of the cavity 206 may beillustrated for ease of explanation.

The alignment fiducial 204 may include a first portion 204A along afloor 212 of the wafer pod 202 and a second portion 204B along a rearwall 214 of the wafer pod 202. The rear wall 214 may be opposite to thedoor 208. The door 208 may also be referred to as a front wall. Asdiscussed above, the first portion 204A may extend along an axis ofentry. Also, the second portion 204B may extend along a vertical axis(e.g., along a same direction as a central vertical axis discussedabove). Accordingly, when a gripper hand is aligned with the alignmentfiducial 204 along both the first portion 204A and the second portion204B, the gripper hand may have its movement constrained around both thevertical axis and the axis of entry.

In various embodiments, a wafer pod may include multiple cavities formultiple wafers. The multiple cavities may be arrayed (e.g., displaced)along the vertical axis, such as where additional cavities may bereproduced above and/or below the cavity 206 (e.g., below the floor 212,where the floor 212 acts as a ceiling for another cavity of a multiplecavity wafer pod.

FIG. 2B is a side cross sectional view of the wafer pod 202 with thealignment fiducial 204, in accordance with some embodiments. The firstportion 204A of the alignment fiducial 204 may be along the floor 212 ofthe cavity 206 while the second portion 204B of the alignment fiducial204 may be along the rear wall 214 of the cavity 206. Also, the firstportion 204A and the second portion 204B of the alignment fiducial 204may not be continuous (e.g., connected). However, the first portion 204Aand the second portion 204B of the alignment fiducial 204 may becontinuous in other embodiments.

FIG. 3 is a partial transparency diagram of a wafer pod 302 withdifferent configurations of a center point sensor 322A or 322B, inaccordance with some embodiments. Similar to FIG. 2A, the wafer pod 302of FIG. 3A may be hollow, with a cavity 306 and a door 308, drawn inphantom with dotted lines, to allow for ingress and egress from thecavity 306 of the wafer pod 302. The sides of the wafer pod 302 mayinclude exterior grips 310 or handles to facilitate movement of thewafer pod 302. The wafer pod 302 is illustrated as a partialtransparency diagram 300 in which features of the cavity 306 may beillustrated for ease of explanation.

The wafer pod 302 may include a center point sensor 322A or 322B. Asdiscussed above, the center point sensor 322A or 322B may be configuredto detect when a center point fiducial of a dummy wafer is along acentral vertical axis 324 between a center point of a floor 312 and aceiling 326 of the wafer pod 302. Stated another way, the center pointsensor 122 may be configured to sense when the center point fiducial 120of a dummy wafer 105A is aligned with a central vertical axis 324 withinthe cavity of the wafer pod 302.

The center point sensor may be disposed along either the floor 312 orthe ceiling 326 of the wafer pod 104. For example, the center pointsensor 322 may emit radiation in a collimated beam from either the floor312 to terminate at the ceiling 326 or from the ceiling 326 to terminateat the floor 312. The center point sensor may be configured to sensewhen the beam, emanating from the floor 312 or the ceiling 326 isreflected from the center point fiducial of a dummy wafer. For examplethe center point sensor 322A or 322B may include a laser emitter thatemits a laser. This laser may be sensed in reflection by a laser sensorcollocated with the laser emitter at the center point sensor 322A or322B. The center fiducial may produce a unique property in thereflection, such as a reflection with a particular intensity or certainwavelengths. The laser emitter may include a photoelectric emitter thatemits collimated radiation as a line or beam to terminate at a point.Also, the laser sensor may include a photoelectric sensor configured todetect particular types of the collimated radiation as reflected off ofthe center point fiducial of a dummy wafer.

FIG. 4 is a block diagram of various functional modules of a wafer podalignment functional module, in accordance with some embodiment. Thewafer pod alignment functional module 402 may be part of a wafer podalignment system that includes the robotic arm and the wafer poddiscussed above. The wafer pod alignment functional module 402 mayinclude a processor 404. In further embodiments, the processor 404 maybe implemented as one or more processors.

The processor 404 may be operatively connected to a computer readablestorage module 406 (e.g., a memory and/or data store), a networkconnection module 408, a user interface module 410, and a controllermodule 412. In some embodiments, the computer readable storage module406 may include wafer pod alignment process logic that may configure theprocessor 404 to perform the various processes discussed herein. Thecomputer readable storage may also store data, such as sensor datacollected by sensors, data for identifying an displacement depth,identifiers for a dummy wafer, identifiers for a robotic arm,identifiers for a gripper hand, identifiers for a sensor, and any otherparameter or information that may be utilized to perform the variousprocesses discussed herein.

The network connection module 408 may facilitate a network connection ofthe wafer pod alignment system with various devices and/or components ofthe wafer pod alignment system that may communicate within or externalto the wafer pod alignment functional module 402. In certainembodiments, the network connection module 408 may facilitate a physicalconnection, such as a line or a bus. In other embodiments, the networkconnection module 408 may facilitate a wireless connection, such as overa wireless local area network (WLAN) by using a transmitter, receiver,and/or transceiver. For example, the network connection module 408 mayfacilitate a wireless or wired connection with an alignment sensor,center point sensor, the processor 404 and the controller module 412.

The wafer pod alignment functional module 402 may also include the userinterface module 410. The user interface may include any type ofinterface for input and/or output to an operator of the wafer podalignment system, including, but not limited to, a monitor, a laptopcomputer, a tablet, or a mobile device, etc.

The wafer pod alignment functional module 402 may include a controllermodule 412. The controller module 412 may be configured to controlvarious physical apparatuses that control movement or functionality ofthe robotic arm and/or components of the robotic arm. For example, thecontroller module 412 may be configured to control movement orfunctionality for at least one of a gripper hand, a gripper handsurface, an alignment sensor, a center point sensor, and/or a wafer poddoor. For example, the controller module 412 may control a motor thatmay move at least one of a gripper hand, a sensor, a sensor platform,and/or a door of a wafer pod. The controller may be controlled by theprocessor and may carry out the various aspects of the various processesdiscussed herein.

FIG. 5 is a flow chart of a wafer pod alignment entry process 500, inaccordance with some embodiments. The wafer pod alignment entry processmay be performed by a wafer pod alignment system, as discussed above. Itis noted that the process 500 is merely an example, and is not intendedto limit the present disclosure. Accordingly, it is understood thatadditional operations may be provided before, during, and after theprocess 500 of FIG. 5, certain operations may be omitted, certainoperations may be performed concurrently with other operations, and thatsome other operations may only be briefly described herein.

At operation 502, a robotic arm gripper hand (e.g., gripper hand of arobotic arm) of the wafer pod alignment system may receive a dummywafer. As discussed above, the dummy wafer may include a center pointfiducial which may be detectible by a center point sensor which confirmswhen the dummy wafer is at a desired location within a cavity of a waferpod. The desired location may be at any desired location within thewafer pod, not necessarily at the very center of the wafer pod. Forexample, the desired location may be closer to the rear wall of thewafer pod than the door (e.g., the front wall) of the wafer pod.

At operation 504, a wafer pod alignment system may detect an alignmentorientation based on alignment sensor data (e.g., data produced todetermine the alignment orientation, or as produced by the alignmentsensor). As introduced above, alignment orientation may be anorientation of the robotic arm gripper hand that is aligned with analignment fiducial that defines the robotic arm gripper hand'sorientation relative to an axis of entry and a vertical axis of thewafer pod. Stated another way, the alignment orientation may restrictmovement of the robotic arm gripper hand along two degrees of freedom(e.g., around an axis of entry and a vertical axis) so that a wafermanipulated by the wafer hand may move into and/or out of a wafer podwithout undesirably impacting a side wall of the wafer pod. Thealignment orientation may be saved for future reference. For example,the alignment orientation may be used when not transporting a dummywafer, but when moving a gripper hand (e.g., a robotic arm gripper hand)for deposit or retrieval of a wafer from the wafer pod.

At operation 506, the robotic arm gripper hand may enter the wafer pod,as oriented with the alignment orientation. As discussed above, movingwith the alignment orientation allows the robotic arm gripper hand tomove in a manner into and out of the wafer pod so as to allow a waferheld by the robotic arm gripper hand to enter or exit the wafer podwithout impacting a sidewall of the wafer pad.

At operation 508, the robotic arm gripper hand may detect a displacementdepth into the wafer pod. As introduced above, the dummy wafer mayinclude a center point fiducial that may be detected by a center pointsensor of the wafer pod. When oriented with the alignment orientation,the dummy wafer may travel along the axis of entry and move the centerpoint fiducial of the dummy wafer toward the center point sensor. Thewafer pod alignment system may confirm that the dummy wafer is in thedesired location when the center point sensor detects the center pointfiducial. In certain embodiments, this may be because the center pointsensor detects whether the center point fiducial has reached a centralvertical axis of the wafer pod. The displacement depth may characterize(e.g., indicate) a displacement of the robotic arm gripper hand from arest position (e.g., outside of the wafer pod from where the robotic armgripper hand may receive a wafer or begin interacting with the waferpod) to an extend position (e.g., from where the center point detectordetects the center point fiducial). The displacement depth may be savedfor future reference (e.g., for use when not transporting a dummy wafer,but when transporting a wafer for deposit or retrieval from the waferpod).

At operation 510, the robotic arm gripper hand may retract the dummywafer. The dummy wafer may be retracted by moving in the alignmentorientation along the axis of entry out of the cavity of the wafer pod.This may be a reverse movement from the movement made by the robotic armgripper hand in operation 506, when the robotic arm gripper hand enteredthe wafer pod. This reverse position may terminate at a rest positionfor which the robotic arm gripper hand may be reoriented for otheraction apart from interacting with the wafer pod, or at a position forreceiving or removal of a wafer from the robotic arm gripper hand.

At operation 512, the dummy wafer previously secured by the robotic armgripper hand may be replaced by a wafer that is to be stored within thewafer pod. The wafer that is to be stored within the wafer pod may be awafer of similar dimensions to the dummy wafer, and thus may bemanipulated in a same way as the dummy wafer was manipulated inpreviously operations (e.g., moved by the robotic arm gripper hand inthe alignment orientation).

At operation 514, the wafer may be placed within the wafer pod by therobotic arm gripper hand in accordance with the alignment orientationdetermined in operation 504 and in accordance with the displacementdepth determined in operation 514. For example, the wafer may be movedwith a same type of motion that moved the dummy wafer in operation 506.Specifically, the robotic arm gripper hand may be moved in the alignmentorientation so that the wafer may enter the wafer pod without impacting(e.g., avoiding) a side wall of the wafer pod. Also, the wafer may bedisplaced into the wafer pod at the displacement depth so that the waferpod is at a desired depth within the wafer pod without being too closeto the rear wall of a wafer pod (e.g., without impacting the rear wallof the wafer pod) and without being too close to a door or front wall ofa wafer pod (e.g., so that the wafer does not hinder the door of thewafer pod from closing). In certain embodiments, the alignmentorientation may be determined with each entry of a wafer to a wafer pod,rather than saving the alignment orientation for use with subsequentwafers (e.g., in subsequent movement of the robotic arm gripper hand).

In various embodiments, the movement of wafers may be termed as arobotic arm routine which may be performed in various iterations toplace multiple wafers into a wafer pod. For example, as discussed above,a wafer pod may include multiple cavities in which wafers may be storedwithin the wafer pod. After determining the alignment orientation andthe displacement depth for one of the cavities, a correspondingalignment orientation and displacement depth may be inferred for theother cavities, but with a corresponding displacement along an axis,such as along a vertical axis for each respective cavity. Accordingly,the robotic arm gripper hand may perform multiple iterations of therobotic arm routine to transfer multiple wafers between differentcavities at different times, where each wafer may be transferred in asame manner but with different cavities at different verticaldisplacements.

FIG. 6 is a flow chart of a wafer pod alignment exit process 600, inaccordance with some embodiments. The wafer pod alignment exit process600 may be performed by a wafer pod alignment system, as discussedabove. It is noted that the process 600 is merely an example, and is notintended to limit the present disclosure. Accordingly, it is understoodthat additional operations may be provided before, during, and after theprocess 600 of FIG. 6, certain operations may be omitted, certainoperations may be performed concurrently with other operations, and thatsome other operations may only be briefly described herein.

At operation 602, the wafer pod alignment system may determine analignment orientation and displacement depth for a wafer pod. Thedetermination of the alignment orientation and displacement depth may beretrieved from a data store, such as a computer readable storage asdiscussed above. The original determination of the alignment orientationand displacement depth stored in the database may be determined asdiscussed in FIG. 5 and will not be repeated here for brevity.

At operation 604, the robotic arm gripper hand may enter the wafer pod,as oriented with the alignment orientation. As discussed above, movingwith the alignment orientation allows the robotic arm gripper hand tomove in a manner into and out of the wafer pod so as to allow a waferheld by the robotic arm gripper hand to enter or exit the wafer podwithout impacting a sidewall of the wafer pad.

At operation 606, the robotic arm gripper hand may retrieve the waferwithin the wafer pod. The gripper hand may retrieve a wafer based on anassumption that the wafer had been placed within the wafer pod at thedisplacement depth determined in operation 602. The gripper hand mayretrieve the wafer by securing the wafer as known in the art. Forexample, the gripper hand may retrieve the wafer by sliding under awafer and raising the wafer above a floor on which the wafer restedwhile within the wafer pod. In other embodiments the gripper hand mayalso grip onto the wafer to secure the wafer within the gripper hand.The gripper hand may also retrieve the wafer by retracting the roboticarm gripper hand, with the secured wafer, out of the wafer pod. Forexample, the wafer may be retracted by moving along the axis of entryout of the cavity of the wafer pod. This may be a reverse movement fromthe movement made by the robotic arm gripper hand in operation 604, whenthe robotic arm gripper hand entered the wafer pod.

In an embodiment, a wafer pod includes: a cavity configured to receiveand store a wafer; an alignment fiducial within the cavity, wherein: thealignment fiducial comprises two lines orthogonal to each other, and thealignment fiducial is configured to be detected by a robotic armalignment sensor disposed on a robotic arm, wherein the alignmentfiducial defines an alignment orientation for a robotic arm gripper handto enter into the cavity.

In another embodiment, a system includes: a gripper hand configured tosecure a wafer; a robotic arm comprising an alignment sensor configuredto detect alignment of the gripper hand to an alignment fiducial withina cavity of a wafer pod, wherein the robotic arm is configured to:determine an alignment orientation for the gripper hand to move into thecavity based on the alignment, and move the gripper hand in thealignment orientation into the cavity.

In another embodiment, a method includes: collecting alignment sensordata that characterizes alignment of a gripper hand with an alignmentfiducial within a cavity of a wafer pod; determining an alignmentorientation for the gripper hand for entry into the cavity based on thealignment sensor data; and moving the gripper hand in the alignmentorientation into the cavity.

The foregoing outlines features of several embodiments so that thoseordinary skilled in the art may better understand the aspects of thepresent disclosure. Those skilled in the art should appreciate that theymay readily use the present disclosure as a basis for designing ormodifying other processes and structures for carrying out the samepurposes and/or achieving the same advantages of the embodimentsintroduced herein. Those skilled in the art should also realize thatsuch equivalent constructions do not depart from the spirit and scope ofthe present disclosure, and that they may make various changes,substitutions, and alterations herein without departing from the spiritand scope of the present disclosure.

In this document, the term “module” as used herein, refers to software,firmware, hardware, and any combination of these elements for performingthe associated functions described herein. Additionally, for purpose ofdiscussion, the various modules are described as discrete modules;however, as would be apparent to one of ordinary skill in the art, twoor more modules may be combined to form a single module that performsthe associated functions according embodiments of the invention.

A person of ordinary skill in the art would further appreciate that anyof the various illustrative logical blocks, modules, processors, means,circuits, methods and functions described in connection with the aspectsdisclosed herein can be implemented by electronic hardware (e.g., adigital implementation, an analog implementation, or a combination ofthe two), firmware, various forms of program or design codeincorporating instructions (which can be referred to herein, forconvenience, as “software” or a “software module), or any combination ofthese techniques. To clearly illustrate this interchangeability ofhardware, firmware and software, various illustrative components,blocks, modules, circuits, and steps have been described above generallyin terms of their functionality. Whether such functionality isimplemented as hardware, firmware or software, or a combination of thesetechniques, depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans canimplement the described functionality in various ways for eachparticular application, but such implementation decisions do not cause adeparture from the scope of the present disclosure.

Furthermore, a person of ordinary skill in the art would understand thatvarious illustrative logical blocks, modules, devices, components andcircuits described herein can be implemented within or performed by anintegrated circuit (IC) that can include a general purpose processor, adigital signal processor (DSP), an application specific integratedcircuit (ASIC), a field programmable gate array (FPGA) or otherprogrammable logic device, or any combination thereof. The logicalblocks, modules, and circuits can further include antennas and/ortransceivers to communicate with various components within the networkor within the device. A general purpose processor can be amicroprocessor, but in the alternative, the processor can be anyconventional processor, controller, or state machine. A processor canalso be implemented as a combination of computing devices, e.g., acombination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other suitable configuration to perform the functionsdescribed herein.

Conditional language such as, among others, “can,” “could,” “might” or“may,” unless specifically stated otherwise, are otherwise understoodwithin the context as used in general to convey that certain embodimentsinclude, while other embodiments do not include, certain features,elements and/or steps. Thus, such conditional language is not generallyintended to imply that features, elements and/or steps are in any wayrequired for one or more embodiments or that one or more embodimentsnecessarily include logic for deciding, with or without user input orprompting, whether these features, elements and/or steps are included orare to be performed in any particular embodiment.

Additionally, persons of skill in the art would be enabled to configurefunctional entities to perform the operations described herein afterreading the present disclosure. The term “configured” as used hereinwith respect to a specified operation or function refers to a system,device, component, circuit, structure, machine, etc. that is physicallyor virtually constructed, programmed and/or arranged to perform thespecified operation or function.

Disjunctive language such as the phrase “at least one of X, Y, or Z,”unless specifically stated otherwise, is otherwise understood with thecontext as used in general to present that an item, term, etc., may beeither X, Y, or Z, or any combination thereof (e.g., X, Y, and/or Z).Thus, such disjunctive language is not generally intended to, and shouldnot, imply that certain embodiments require at least one of X, at leastone of Y, or at least one of Z to each be present.

It should be emphasized that many variations and modifications may bemade to the above-described embodiments, the elements of which are to beunderstood as being among other acceptable examples. All suchmodifications and variations are intended to be included herein withinthe scope of this disclosure and protected by the following claims.

What is claimed is:
 1. A method, comprising: collecting alignment sensordata that characterizes alignment of a gripper hand with an alignmentfiducial within a cavity of a wafer pod, wherein the alignment fiducialcomprises a first line extending along a central vertical axis of a rearwall of the cavity and a second line extending along a centralhorizontal axis of a ceiling or floor of the cavity, wherein the firstand second lines are orthogonal to each other; determining an alignmentorientation for the gripper hand for entry into the cavity based on thealignment sensor data, wherein the alignment sensor data is collected byan alignment sensor disposed on a robotic arm configured to move thegripper hand; and moving the gripper hand in the alignment orientationinto the cavity.
 2. The method of claim 1, wherein the moving thegripper hand in the alignment orientation into the cavity avoids contactbetween a side wall of the wafer pod with a wafer held by the gripperhand.
 3. The method of claim 1, further comprising: detecting a centerpoint fiducial on a dummy wafer within the cavity; and receiving adisplacement depth indicating a displacement value of the gripper handwhen the center point fiducial of the dummy wafer is detected.
 4. Themethod of claim 3, wherein the displacement depth is used to positionthe dummy wafer to avoid contact with both a rear wall of the wafer podand a door of the wafer pod.
 5. The method of claim 1, wherein thealignment sensor is a laser sensor mounted on the robotic arm.
 6. Themethod of claim 1, wherein the alignment sensor data is collected whilethe gripper hand is outside of the cavity.
 7. A method, comprising:storing a wafer in a cavity of a container; providing an alignmentfiducial within the cavity, wherein the alignment fiducial comprises afirst line extending along a central vertical axis of a rear wall of thecavity and a second line extending along a central horizontal axis of aceiling or floor of the cavity, wherein the first and second lines areorthogonal to each other; and detecting the alignment fiducial by arobotic arm alignment sensor disposed on a robotic arm configured toretrieve the wafer from the container, wherein the alignment fiducialdefines an alignment orientation for a robotic arm gripper hand to enterinto the cavity.
 8. The method of claim 7, wherein the second lineextends along the central horizontal axis of the floor of the cavity. 9.The method of claim 7, further comprising: detecting when a center pointfiducial of a dummy wafer positioned within the cavity is above or belowa center point sensor provided within the cavity.
 10. The method ofclaim 9, wherein the center point sensor is a laser sensor.
 11. Themethod of claim 10, wherein the laser sensor comprises a laser emitterconfigured to emit a laser beam between a floor and a ceiling of thecavity.
 12. The method of claim 7, wherein the alignment fiducial isconfigured to be detected from outside the wafer pod.
 13. A method,comprising: securing a wafer contained within a cavity of a wafer podwith a gripper hand of a robotic arm; detecting an alignment of thegripper hand to an alignment fiducial within the cavity of the waferpod, wherein the fiducial comprises a first line extending along acentral vertical axis of a rear wall of the cavity and a second lineextending along a central horizontal axis of a ceiling or floor of thecavity, wherein the first and second lines are orthogonal to each other;and moving the gripper hand based on the detected alignment within thecavity.
 14. The method of claim 13, wherein detecting the alignmentcomprises determining a displacement depth indicating a displacementvalue of the gripper hand when a center point fiducial of a dummy waferheld by the gripper hand is detected by a center point detector locatedon the wafer pod.
 15. The method of claim 14, wherein the displacementdepth is used by the robotic arm to position the dummy wafer to avoidcontact with both a rear wall of the wafer pod and a door of the waferpod.
 16. The method of claim 13, wherein the second line extends alongthe central horizontal axis of the floor of the cavity.
 17. The methodof claim 13, wherein detecting the alignment comprises detecting analignment of a laser line, emitted from an alignment sensor, with thealignment fiducial.
 18. The method of claim 13, further comprisingdetecting when a center point fiducial located on a dummy wafer held bythe gripper hand is positioned within the cavity above or below a centerpoint sensor located within the cavity.
 19. The method of claim 18,wherein the center point sensor is a laser sensor.
 20. The method ofclaim 19, wherein the laser sensor comprises a laser emitter configuredto emit a laser beam between a floor and a ceiling of the cavity.